1. Field of the Invention
The present invention relates to a balloon unit for an endoscope apparatus, and particularly relates to a balloon unit for an endoscope apparatus which is attached to an endoscope for observing small bowel and large bowel.
2. Description of the Related Art
In endoscope apparatuses, balloons which can expand and contract are used for various purposes. For example, in an endoscope apparatus for observing deep alimentary canals such as small bowel and large bowel, an expandable balloon is attached to an endoscope insert part or an endoscope insert supporter (such as a sliding tube or an over tube), so that the endoscope insert part or the insert supporter can be fixed to a viscera by expanding the balloon. In an ultrasonic diagnosis apparatus, an expandable balloon is used to surround an ultrasonic scan part at a tip of an ultrasonic probe and fill an ultrasonic transmitting medium. In an ultrasonic endoscope, an expandable balloon is used to surround an ultrasonic transducer at a tip of an insert part and fill an ultrasonic transmitting medium.
Such a balloon for endoscope is made of an elastic body such as rubber and an end of the balloon is formed in a cylindrical shape having a diameter smaller than an outer diameter of an object to be attached (the endoscope insert part or the insert supporter, for example). When the balloon is attached, the object to be attached is covered with the end of the balloon while enlarging the diameter of the end. Thereafter, thread is wound or a rubber band is fitted over the end of the balloon so as to fix the end of the balloon to the object to be attached.
However, there is a problem that the task of covering the object to be attached with the end of the balloon while enlarging the diameter of the end of the balloon is very onerous and the attachment task is troublesome.
Thus, in Japanese Patent Application Laid-Open No. 5-15487, a method is described in which a balloon is adsorbed and attached on an inner circumferential surface of a cylinder body. According to this method, an inner diameter of the balloon can be enlarged by adsorbing the balloon on the inner circumferential surface of the cylinder body, so that the insert part or the insert supporter can be easily inserted therethrough.
However, the attachment method in Japanese Patent Application Laid-Open No. 5-15487 has problems that a special attachment jig is required and a task of attaching the special attachment jig to the balloon is troublesome and thus the balloon can not be quickly attached.
In addition, the method in Japanese Patent Application Laid-Open No. 5-15487 is adapted to attach a balloon to an endoscope having a fluid supplying and sucking port in an outer circumferential surface of an insert part. If there is no fluid supplying and sucking port in the insert part, it is necessary to insert a tip of a tube deeply into the balloon. Therefore, there are problems that the task of attaching the balloon is troublesome and air-tightness between the balloon and the insert part after attachment is low.
The present invention is provided in view of the above problems and it is an object of the present invention to provide a balloon unit for an endoscope apparatus which can be quickly and easily attached to an object to be attached such as an endoscope insert part or an insert supporter.